This invention relates to apparatus and methods for wire-tying one or more objects, including, for example, wood products, newspapers, magazines, pulp bales, waste paper bales, rag bales, pipe, or other mechanical elements.
A variety of automatic wire-tying machines have been developed, such as those disclosed in U.S. Pat. No. 5,027,701 issued to Izui and Hara, U.S. Pat. No. 3,889,584 issued to Wiklund, U.S. Pat. No. 3,929,063 issued to Stromberg and Lindberg, U.S. Pat. No. 4,252,157 issued to Ohnishi, and U.S. Pat. No. 5,746,120 issued to Jonsson. The wire-tying machines disclosed by these references typically include a track that surrounds a bundling station where a bundle of objects may be positioned, a feed assembly for feeding a length of wire about the track, a gripping assembly for securing a free end of the length of wire after it has been fed about the track, a tensioning assembly for pulling the length of wire tightly about the bundle of objects, a twisting assembly for tying or otherwise coupling the length of wire to form a wire loop around the bundle of objects, a cutting assembly for cutting the length of wire from a wire supply, and an ejector for ejecting the wire loop from the machine.
One drawback to conventional wire-tying machines is their complexity. For example, a variety of elaborate hydraulically-driven, or pneumatically-driven actuation systems are commonly used for performing such functions as securing the free end of the length of wire, for cutting the length of wire from the wire supply, and for ejecting the wire loop from the machine. Track assemblies also typically require some type of spring-loaded hydraulic or pneumatic system to actuate the track between a closed position for feeding the wire about the track, and an open position for tensioning the wire about the bundle of objects.
Such hydraulic or pneumatic actuation systems require relatively expensive cylinder and piston actuators, pressurized lines, pumps, valves, and fluid storage facilities. These components not only add to the initial cost of the wire-tying machine, but also require considerable maintenance. The handling, storage, disposal, and cleanup of fluids used in typical hydraulic systems also presents issues related to safety and environmental regulations.
This invention relates to improved apparatus and methods for wire-tying one or more objects. In one aspect of the invention, an apparatus includes a track assembly, a feed and tension assembly, and a twister assembly having a gripping mechanism engageable with the length of wire, a twisting mechanism including a twisting motor operatively coupled to a twist pinion engageable with the length of wire, the twist pinion being rotatable to twist a portion of the length of wire to form a knot, a cutting mechanism engageable with the length of wire proximate the knot, and an ejecting mechanism engageable with the length of wire to disengage the length of wire from the twister assembly. The gripping mechanism includes a gripper block having a wire receptacle formed therein, an opposing wall positioned proximate the wire receptacle, and a gripper disc constrained to move toward the opposing wall to frictionally engage with the length of wire disposed within the wire receptacle, the gripper disc being driven into frictional engagement with the length of wire and pinching the length of wire against the opposing wall when the drive motor is operated in the tension direction. Thus, the wire is secured using a simple, passive, economical, and easily maintained gripping mechanism.
While a combination of various subcombination assemblies combine to make this overall wire-tying apparatus and method, several of the sub-assemblies are themselves unique and may be employed in other wire tying apparatus and methods. Thus, the invention is not limited to only one combination apparatus and method.
For example, a unique passive wire gripping sub-assembly includes a wire receptacle having a slot sized to receive a first passage of wire in one portion thereof and a second passage of wire in another portion thereof, a passive gripper disk being frictionally engageable with the second passage of wire to hold the free end of the wire.
In the twister assembly, the assembly includes a multi-purpose cam rotatably driven by the twister motor, and the gripping mechanism includes a gripper release engageable with the gripper disk and actuatable by the multi-purpose cam.
A unique feature of the track assembly includes multiple ceramic or high hardness steel sections or segments disposed proximate to a corner guide at the corners of the track assembly, the sections each having a curved face at least partially surrounding the wire guide path to redirect the motion of the length of wire about the corners. The sections resist gouging from the relatively sharp free end of the length of wire as it is guided along the wire path, reducing mis-feeds, improving reliability, and enhancing durability of the apparatus. The sections are less expensive to manufacture for replacement and, by adding more sections to larger corner guides, the corner radius of the wire path may be increased with little cost increase.
In one aspect of the invention, an apparatus includes a track assembly, a feed and tension assembly, and a twister assembly having a twist motor coupled to a rotatable twist axle having a first multi-purpose cam, an ejector cam, a drive gear, and a second multi-purpose cam attached thereto, a gripping mechanism engageable with the length of wire and having a gripper cam follower engageable with the second multi-purpose cam, the gripping mechanism being actuatable by the second multi-purpose cam, a twisting mechanism having a twist pinion engageable with the length of wire, the twist pinion being actuatable by the drive gear and rotatable to twist a portion of the length of wire to form a knot, a cutting mechanism engageable with the length of wire proximate the knot and having a cutting cam follower engageable with the first multi-purpose cam, the cutting mechanism being actuatable by the first multi-purpose cam; and an ejecting mechanism engageable with the length of wire to disengage the length of wire from the twister assembly and having an ejecting cam follower engageable with the ejector cam, the ejecting mechanism being actuatable by the ejector cam. Thus, the primary functions of the twisting assembly are cam-actuated, eliminating more expensive and complex actuating mechanisms, and improving the economy of the apparatus.
Another aspect of the invention is a unique wire accumulation drum through which the length of wire is axially fed and from which the length of wire tangentially exits at its periphery to be engaged by a drive wheel. The accumulator drum is shown in alternative forms.
Another aspect of the invention is a unique feed and tension assembly pulling wire axially through a drum, then tangentially off the drum to a feed drive wheel and then back onto the periphery of the drum when tensioning the wire. Alternative forms are shown.
Another aspect of the invention is a simple shaft driven drive for twisting the wire, gripping the wire, releasing the twisted wire, and cutting the wire.
Another aspect of the invention is a passive wire gripper that uses the friction of the wire to cause the wire free end to be squeezed and held against movement out of the twister mechanism. The passive wire gripper has several alternative forms.
These and other benefits of the present invention will become apparent to those skilled in the art based on the following detailed description.